Stormwater design and management plays an important role in the site planning and design process, and stormwater design practices will likely need to evolve to accommodate future climate changes. Potential issues that may affect stormwater design include more frequent and extreme flooding events as a result of sea level rise and high tides (see for example the changes occurring in Miami Beach), more severe storm events that increase the quantity of runoff (see information here), changes in precipitation patterns, and higher water tables. The loss of wetlands and other natural areas that provide flood mitigation and storm protection services, coupled with construction of impervious surfaces in urban and suburban landscapes, has the potential to exacerbate these flooding events. An example is the impact of impervious surfaces and loss of wetlands on flooding in Houston during Hurricane Harvey in 2017 (see information here and here). Increased stormwater runoff also has the potential to adversely impact water quality and increase soil loss and erosion.
Many of the respondents to our survey agreed that additional capacity should be included in stormwater design as a response to climate change. However, in comments they also advocated for the use of reclaimed water, on-site infiltration, green roofs and other types of urban green infrastructure, restored wetlands, and low impact development (LID) practices. Most agreed that permeable paving should be used more widely; however, some pointed out problems such as clogging, lack of maintenance, and problems with sand bases in high traffic areas. Other landscape architects have indicated that reclaimed water use remains problematic in at least some locations for design and regulatory reasons.
Designing to reduce stormwater flows and volume, limiting the areas of a site covered by impervious surfaces, and maximizing areas for stormwater infiltration through the use of green infrastructure are tried and true stormwater design practices that can also help address future climate change and flooding issues. Stormwater management will also continue to play an important role in maintaining water quality through reduced flows of sediment and pollutants to water bodies. However, ongoing work in Miami Beach to raise streets and install stormwater pumps as a response to flooding shows that if people are to remain in vulnerable areas, green infrastructure may only provide part of the solution.
Web-based Resources
EPA Climate Adaptation and Stormwater Runoff: https://www.epa.gov/arc-x/climate-adaptation-and-stormwater-runoff
Naturally Resilient Communities: Nature Based Solutions to Address Flooding: http://nrcsolutions.org/
University of Central Florida Stormwater Management Academy: http://stormwater.ucf.edu/
Research
Handley et al. (2007). Adapting Cities for Climate Change: The Role of the Green Infrastructure
Pandey et al. (2003). Rainwater Harvesting as an Adaptation to Climate Change
Pyke et al. (2011). Assessment of Low Impact Development for Managing Stormwater with Changing Precipitation Due To Climate Change